Building construction unit comprising light-polarizing material



350-404 7 R 74 Search Room June 29, 1943. E. H. LAND 2,323,059

BUILDING CONSTRUCTION UNIT COMPRISING LIGHT-POLARIZING MATERIAL Filed Nov. 7, 1940 ted June 29, 1943 BUILDING CONSTRUCTION UNIT COMPRIS- ING LIGHT-POLARIZING MATERIAL Edwin H. Land, Cambridge, Mass., assignor to Polaroid Corporation, Dover, Del., a corporation of Delaware Application November 7, 1940, Serial No. 364,672

1 Claim.

This invention relates to a new and improved building construction unit, and more specifically to a buildingconstruction unit of the character described, adapted, in connection with a suitable light source, to provide a panel or other area of a predetermined color or colors.

An object of the invention is to provide a building construction unit comprising a pliable, flexible sheet of sufllcient body or rigidity to retain its form when positioned within a suitable frame or other supporting member, said sheet being translucent -or transparent and being adapted, in connection with a suitable light source, to provide a brilliantly colored panel or similar construction element.

Other objects of the invention are to provide a sheet of the character described comprising a light-polarizing material intimately bonded or cemented to a suitable doubly refractive material such as a fractional wave retardation element; to provide in connection with such a sheet suitable frame or other construction elements for supporting said sheet; to provide a sheet of the character described adapted for use as a closure element, such for example as a wall closure element or the like; to provide in connection with said sheet and said mounting means a suitable light source positioned with respect thereto so as to project thereon a beam for illuminating said sheet; to provide a sheet of the character described which is substantially impervious to-moisture, which is of such strength, resiliency and rigidity as to be readily shipped and handled, which may be cut or formed at the building site, which is durable, and which retains its optical properties indefinitely.

Other objects of the invention are to provide a wall closure element comprising a structural frame comprising stud and joist elements, and means associated therewith for positioning with respect thereto a panel or wall closure element of the character described, said wall closure element being adapted to resolve an incident beam of light into predetermined colors, whereby said assemblage may be employed not only as a wall closure but as an artistic unit of great beauty in architectural designs and building constructions.

Other objects of the invention will in part be obvious and will in part appear hereinafter.

The invention accordingly comprises the features of construction, combination of elements, and arrangement of parts which will be exemplifled in the construction hereinafter set forth and the scope of the application of which will be indicated in the claim.

For a fuller understanding of the nature and objects of the invention reference should be had to the following detailed description taken in connection with the accompanying drawing, in which:

Figure 1 is a perspective view with parts broken away of a wall closure element and associated frame embodying one form of the invention; and

Fig. 2 is a sectional view of a modification of the device shown in Fig. 1.

In many industrial uses, for example in fairs, museums, parks, theatrical displays, advertising devices and the like, it is highly desirable that vivid color be employed in connection with the construction of buildings, fences, display panels, signs, and other structural units, and it is espe cially desirable that such vivid color be employed in connection with night-time display. While color is in itself desirable as attracting attention to the display or to the building, something more than simple color or simple color design is required. It has been found highly desirable to employ a changing color pattern or design, and more especially to employ such changing colors in large unit areas and over large surfaces, and where possible so to construct a building or display that the structural units which enter into the building or display are given the effect of being variously colored and of changing in color from time to time as the position of an observer changes with respect thereto.

Attempts to secure the desired result have resulted in the use of floodlighting, where the building display or other structure is illuminated with lights of difierent colors, or in the employment of large banks of incandescent lights of varying colors, or in the employment of illuminating devices of the type of neon or mercury vapor lamps or the like in large quantity adjacent the structure to be illuminated.

This invention contemplates a totally different device and procedure for illuminating areas of any desired size in building constructions or the like. A typical embodiment thereof is shown in the drawing and includes a light, structural frame comprising, for example, the stud elements II and the joist elements l2, suitably fastened together to provide a panel opening of any predetermined area and shape. These joist and stud elements may be provided with suitable abutment portions I3 adapted to receive a panel-closing element l4. Suitable means may be provided,

such for example as the clamping ring l5, for holding the panel-closure element H in position within the frame and against the abutment portion 13. The joists and stud may be provided with depending lips or detents I6, which may be integral with the studs and joists, and which may be positioned so as to. hold the ring element I5 against the panel closure element H. The rin element 15 may be forced into operative engagement with the panel element I4 over the portions l6, and to aid in assembling the elements in the manner described, the ring element may be somewhat resilient.

The panel element l4 preferably comprises a unitary sheet of set or hardened transparent plastic material, or it may comprise a plurality of superimposed layers or films of plastic materials with an outer protective glass layer. One of said layers, preferably an intermediate layer 20, comprises a light-polarizing material, for example any of the polarizing materials sold under the trade name Polaroid, which are available as thin plastic films of relatively large area and considerable tensile strength.

On the inner face of this light-polarizing element 20 there may be affixed a somewhat thicker sheet 2| of doubly refractive material, such for example as Cellophane, or other birefringent plastic material, such for example as a sheet of cellulose acetate formed with its molecules in oriented relation so as to impart birefringence to the sheet, or the sheet 2| may comprise ethyl cellulose stretched under tension when hot, so as to render it birefringent. The birefringent sheet 2| is preferably so positioned with respect to the polarizing sheet 20 that the optic axes of the birefringent sheet are neither parallel nor perpendicular to the polarizing axis of the polarizing sheet. It may then be laminated or bonded theremately bonded sheets or films of such thickness as to give to the finished panel sufllcient rigidity and weight, so that when placed in position within the frame it will maintain its position and will resist normal knocks and blows to which it may be subjected in usage. It has been found that a total thickness of from .020 to .030 of an inch may be adequate, although the panel element may, if desired, be thicker or thinner, depending upon the uses to which it is to be put. It is to be understood, however, that the element [4 is not intended to impart structural strength to the building assembly, but is merely intended for use as a closure element within the frame formed by the elements II and I2.

With the assembly in position, brilliant color effects may be achieved by throwing upon the panel from within the structure a beam of polarized light. Preferably this should be done from a light source closely adjacent the panel, as under these circumstances widely varied colors, changing colors, and other striking effects may be secured as an observer walks past the building structure, even without moving parts associated with the light source.

A satisfactory construction is .shown, for example, in Fig. 2. Here the joist elements I2 have been somewhat extended to provide supporting means for a plurality of light sources 30 positioned within suitable reflectors 32, and adapted to cast a beam of light from within upon the panel M. The reflectors and joists may be provided with mounting means 35 adapted to receive light-polarizing elements 35, which may, for example, comprise sheets of the polarizing materials sold under the trade name of Polarold." Polarizing elements 36 are preferably so positioned with respect to panel N that their polarizing axes are neither parallel nor perpendicular to the optical axes of the birefringent element 2|. Under these circumstances an observer positioned on the opposite side of panel l4 from light sources 30 will see the panel illuminated as a panel of solid color, and as he moves his position and thus alters the angle at which he views the panel, the color thereof will apparently change.

It will be understood that many variations of the above construction may be made within the scope of the invention. For example, in a useful modification both layers 2| and 22 may represent layers of polarizing material having a layer 20 of birefringent material bonded therebetween. The relative positioning of said layers with respect to their cpical axes depends in large measure on the particular birefringent material used. It may be stated generally, however, that a single layer of birefringent material should be so positioned that neither of its axes is parallel or perpendicular to the polarizin axis of either polarizing layer. The most vivid color effects are obtained if the polarizing layers are positioned with their axes relatively perpendicular or parallel and with the axes of the birefringent material at approximately 45 to the axes of the polarizing layers. If more than one layer of birefringent material is used in element 20, with no layer having either axis parallel or perpendicular to any axis of any other layer, then their positioning relative to the axes of the polarizing layers is less important, and vivid color effects can be obtained in virtually any such position.

An assembly of the above type may be used as shown in Fig. 1, or it may be provided with protecting layers of glass or other transparent plastic material such, for example, as the material sold as Plexiglas. Such a unit may be used as in Fig. 2, in which case polarizers 36 will be eliminated. Improved results will be obtained from this combination if in place of polarizers 36 there are susbtituted light-diffusing elements such, for example, as plates of ground glass. It should also be noted that a unit of this type may be used without special illumination if it be used as a window or screen in a relatively well lighted room such, for example, as a restaurant or in connection with a display. Furthermore, in such uses, this type of unit may be used as a translucent screen of brilliant and changing coloring'by using at the side nearer the light source a protecting layer of ground glass or other light-diffusing, plastic material.

It will be obvious that with structures of the type herein described and claimed various building constructions may be made. For example, the panel elements may be employed in the construction of walls or blinds, or pillars, or in the construction of colored panels forming a part of the face of a theater or other place of amusement, or generally wherever the use of color may be desirable in the building trade. It will be obvious that the frame may be shipped to the place of work in an unassembled condition and there erected, and the panel element I4 may also be shipped to the place of work, either in flat condition or as a roll, and there assembled with the frame. The resulting structural unit comprising the frame and panel may have sufficient strength to form a part of the structural assembly, i. e., a plurality of the frame elements may be mounted adjacent or upon each other to build up a large area, the structure of which comprises the frame elements themselves, and the panel elements It may then be employed to close the openings, i. e., as wall closure elements.

It is to be understood that the invention is not to be limited to the form shown in the drawing, but that the frame element may be of any desired shape and size, and may, if desired, be mounted for relative rotation or other movement with respect to the light sources.

Since certain changes may be made in the above article and different embodiments of the invention could be made without departing from the scope thereof, it is intended that all matter contained in the above description or shown in the accompanying drawing shall be interpreted as illustrative and not in a limiting sense.

It is also to be understood that the following claim is intended to cover all the generic and Search Room specific features of the invention herein described, and all statements of the scope of the invention which, as a matter of language, might be said to fall therebetween.

Having described my invention, what I claim as new and desire to secure by Letters Patent is:

A structural assembly comprising, in combination, a plurality of stud and joist elements, means for positioning said elements to form a frame, said elements being provided with flange means for the reception within said frame of a wall closure element, a wall closure element positioned within said frame, said wall closure element comprising a plurality of sheets of sheet plastic material bonded together, one of said sheets being a lightpolarizing element, another of said sheets being a fractional wave retardation element, said sheets being so positioned with respect to each other that the axes thereof are neither parallel nor perpendicular to each other, a light source held by said frame in a position to direct a beam of light through said wall closure element, and a lightpolarizing element positioned between said source and said Wall closure element, said wall closure element being positioned within said frame with said wave retardation element adjacent said light source.

EDWIN H. LAND. 

